The invention concerns a device for the control of the position of a mobile mechanism by means of a cam driven by a motor to actuate a contact connected with said mechanism. The device according to the invention makes it possible, in case of a failure which does not affect the freedom of movement of the cam, to reset said cam toward a predetermined, accurate and stable position. Such cases of failure are for example a rupture of the connecting mechanism between the motor and the cam, or, when the motor is an electric motor, an electrical failure, or again, if the motor is a hydraulic jack, a leak of the jack or its supply circuit.
The invention applies in particular to regulators controlled by means of a cam to guide the operation of a mechanism, a machine or a motor. The device of the invention is specifically suitable for the control of the operation of the regulator of a metering device for metering flow of fuel in a combustion chamber of a jet engine, because it makes it possible, in case of a failure of the motive device of the cam of the regulator, to maintain operational conditions with respect to the chamber, at an operating level designated "emergency", thus alleviating all catastrophic consequences.